In recent years there has been a resurgence in the search for environmentally sensitive construction materials, or what are referred to widely as “green” construction materials. This has caused the field to re-visit and improve upon some established technologies, such as straw bale construction materials. Though offering certain advantages, especially in view of the abundance of available materials and relatively low baling costs, straw bales tend to be limited in application due to some of their disadvantages. For example, conventional straw bales tend to have poor quality external surfaces (e.g., they are typically unkempt in appearance, with stray fibers protruding from them), they tend to be limited in their insulation capabilities; they tend to be limited in the attainable geometries and/or sizes, or any combination thereof. Accordingly, there is an ongoing need to identify and develop alternative “green” construction materials other than conventional straw bales.
Another issue the building industry has encountered is the lack of a standardized straw bale for construction. This can be particularly problematic when a large quantity of uniform blocks are required, such as when attempting to design and build medium to large sized structures or when designing a plurality of buildings such as in a residential subdivision or otherwise. This is due, in part, to the lack of availability of suppliers offering straw bales having, at a minimum, a common size and weight. As such, contractors have typically been required to adjust their building practices based upon the fluctuating size and quality of the bales produced by a particular farmer's equipment and baling practices.
While the industry could help toward improving this problem, with stringent certifications or standards, such regulation is believed difficult to implement, largely because of the vast range of available processing techniques and variables as to taking straw bales directly from the fields when the contract balers bundle the straw and bind everything with wire, as well as the great fluctuations in the raw material characteristics, and the resulting unpredictability from the combination of the foregoing. What is needed is an alternative technology that lends itself to a common platform that can be employed with consistency and reproducibility.
The agricultural industry is faced with annually disposing of tons of agricultural by-products, such as waste straw, particularly rice straw originating from the oryza sativa plant. For instance, after harvest of the grains of rice, the remaining rice straw stalks remain in the planting areas and require disposal. One method of disposal is to burn the straw. However, burning of this plant, to make room for the following season's crop, is impractical, harmful to the environment and may be unlawful. Additionally, rice straw stalks lack substantive nutritional values, providing little value as a fertilizer or other foodstuff. Further, in some instances, it is possible that the stalks may contain diseases or insects, which especially in combination with its slow decay rate make it impractical to plow the remaining stalk back into the soil.
As an alternative to seeking to dispose of waste agricultural by-products (e.g., straw), attention has been given to efforts at re-cycling or finding uses for the agricultural by-products. Applying such waste materials in the formation of construction materials has been the subject of commonly owned U.S. Pat. No. 6,951,080, and co-pending U.S. patent application Ser. No. 10/807,946 (filed Mar. 24, 2004, U.S. Publication No. 2005/0223671) and Ser. No. 12/187,779 (filed Aug. 13, 2008); the contents of which are hereby expressly entirely incorporated by reference for all purposes.
Other efforts to address uses of waste agricultural by-products are illustrated, without limitation, in U.S. Pat. No. 7,073,306 to Hagaman, entitled Method of Building purports to show a method of building a wall assembly with fibrous material such as straw. U.S. Pat. No. 5,656,129, entitled Method of Producing Fibers From a Straw and Board Products Made There from addresses a method of refining wheat straw into fibers by cutting the straw to a length of between about two and about four inches, wetting the straw, softening the straw by subjecting the straw to pressurized steam and refining the softened straw in a pressurized mechanical refiner to produce fibers capable of being used in the manufacture of cellulosic board products. U.S. Pat. No. 4,058,580 to Flanders addresses a reinforced board manufacturing process whereby a compressed uniform mixture of comminuted lignocelluloses particles, binder and other additives that have a plurality of elongate reinforcing filaments having substantially greater tensile strength and modulus of elasticity than the mixture, embedded therein and bound to the particles by the binder.
Accordingly, not only would it be attractive to provide a construction material effectively comprising agricultural by-products (e.g. recycled straw stalks) that have little other practical use, but it would be especially desirable to provide such a construction material so that it will yield consistent and uniform characteristics, function as a support structure in a building, further provide for multifunctional use, (such as a mounting surface), a surface subject to coating, or both, or any combination thereof.